1. Technical Field
The present invention relates to an image display method in a liquid crystal display and a liquid crystal display and in particular to a liquid crystal display using the liquid crystal mode with high-speed response.
2. Prior Art
As an art for improving the display characteristics of an image displayed on a liquid crystal panel, for example, as disclosed in Published Unexamined Patent Application No. 64-82019, there is a method for the intermittent lighting of backlights in synchronism with the frame period. That is, a plurality of selectively lightable backlights are provided and are lighted and extinguished in sequence with the timing of driving the scanning electrodes of a liquid crystal display. The respective backlights are so arranged as to be lighted right after all image scanning electrodes within individual lighting range have been selected and are extinguished after the lapse of a predetermined period. With respect to each scanning line, a backlight is lighted only during the moment while its contrast ratio is high or otherwise extinguished. It is referred to as blanking that in order to allow an image display only for a desired term in such a manner, a non-image is forcibly displayed during the other terms (including a non-display condition made by extinguishing the backlights). Because of preventing different frames continuous to each other from becoming visible by mixing in one screen during a given time, this blanking can improve the image quality of a display image, especially the display characteristics of a dynamic image.
The background art mentioned above has a problem that the optimal timing for each scanning line cannot be set because the blanking can be performed only in the unit of a backlight. That is, individual scanning lines are successively driven at a slight shift of timing. Accordingly, with different scanning lines, the moment of peak contrast also differs. For a small number of backlights (i.e., when the lighting range of one backlight is wide), the time lag of scanning lines within the lighting range becomes so large as not to be negligible, so that even if optimum for some scanning line, the timing of lighting may not be said to be fit for other scanning lines. To solve this, there occurs the need for an increase in the number of backlights. Ideally, backlights equal in number to the scanning lines need only to be provided, but such an arrangement is difficult in actuality.
Thus, it is an object of the present invention to provide a novel method for improving the display characteristics of an image.
To solve the problems mentioned above, the present invention provides an image display method in a liquid crystal display equipped with a liquid crystal panel which comprises a plurality of gate lines, a plurality of data lines and pixel cells disposed in the shape of a matrix corresponding to their intersections, comprising: a step of selecting a gate line for the display of an image on the liquid crystal panel in a term during the period of displaying one image and moreover supplying an image signal to display the image to the above data line; and a step of again selecting the gate line in a term other than the one during the same period as that of the above-mentioned one term and moreover supplying a non-image signal having a predetermined voltage and different from the image signal to the data line.
Further, the present invention is further directed to a liquid crystal display comprising: a plurality of gate lines; first and second data line groups each comprising a plurality of data lines; a liquid crystal panel divided into a first pixel array and a second pixel array wherein the first pixel array comprises gate lines, data lines in the first data line group and pixel cells disposed in the shape of a matrix corresponding to their intersections and the second pixel array comprises gate lines, data lines in the second data line group and pixel cells disposed in the shape of a matrix corresponding to their intersections; gate line driver for selecting gate lines for each of the first and second pixel arrays; a first data line driver for supplying a signal to data line in the first data line group; a second data line driver for supplying a signal to data line in the second data line group; a controller for controlling the gate line driver so as to select a gate line for each of the first and second pixel arrays for the display of an image on the liquid crystal panel and controlling the first and second data line drivers so as to supply an image signal to display an image to the first and second data line groups in one term during the period of displaying one image and moreover for controlling the gate line driver so as to again select the gate line for each of the first and second pixel arrays and controlling the first and second data line drivers so as to supply a non-image signal having a predetermined voltage and different from the image signal to the first and second data line groups in a term other than the above-mentioned one during the same period as that of the above-mentioned one term.
Each gate line is usually selected only once during the period of displaying one image but selected twice or more in the above arrangement. One is a selection for the image display and the other are selections for the a non-image display (blanking). By selecting the gate line again independently of the image display and making a pixel cell into a condition corresponding to the non-image signal, blanking can be accomplished in the unit of a gate line.